Cross-tenant User Data Migration is Now Generally Available

For mailbox migrations, the source mailbox is deleted after the migration but what happens to the OneDrive data in the source post-migration? Is it moved or copied? Per the documentation, OneDrive accounts with a Hold policy applied will be blocked from migration. To migrate these OneDrive accounts, remove the hold policy, migrate, then reapply the hold as needed on the target tenant. When migrations are complete, a redirect is placed in the location of the user's original OneDrive, so any links to files and folders can continue working in the new location. Is the OneDrive data still available, discoverable, or accessible in the source tenant for legal hold? 

Is a WW tenant the same as a Commerical tenant or is that something else? Per the Cross-tenant OneDrive migration documentation, This feature is not supported for users of the Government Cloud, including GCC, Consumer, GCC High, or DoD. What is Consumer referring to? I have checked multiple commercial tenants that have EAs with the E3, E5, etc. licenses and do not see this add on available. Are there trial licenses available to answer these questions as well as the ones to follow?